Leather-stamping machine.



B. J. MILLER.

LEATHER STAMPING MACHINE. APPLICATION FILED MAR. 19. 1911- 1 256,5551 Patented Feb. 12, 1918.

BERNARD J. MILLER, OF MILWAUKEE, WISCONSIN.

LEATHER-STAMPING MACHINE.-

Specification of Letters Patent.

Patented Feb. 12, 1918.

Application filed March 19, 1917. Serial No. 155,723.

To all whom it may concern:

Be it known that I, BERNARD J. MILLER, a citizen of the United States, and resident of Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Leather- Stamping Machines; and I do hereby declare that the following isa full, clear, and exact description thereof.

My invention relates to new and useful improvements in leather stamping and embossing machines, particularly in the means for regulating the amount of pressure exerted upon the leather.

The machines which are adapted for embossing, graining and otherwise stamping sheets of ordinary leather to represent hides and skins of various kinds and are now in use in the larger factories devoted to the manufacture of leather goods, are not equipped with any mechanical means for preventing the excessive pressing of the sheets of leather, but depend upon the ability and skill of the operators. Even the most skilful operators spoil one or more sheets of leather during a days work by permitting the same to remain between the pressing jaws of the machines too great a length of time. Not only the excessive pressure ruins the leather sheets, but also the continued application of heat from the jaws for any too great a length of time.

In most devices or machines of this character the sheets of leather to be stamped are placed between the clamping jaws which carry the dies, the operator then tripping a lever to actuate parts of the machine to bring the jaws together. The said jaws will remain thus clamped together until the operator again trips the lever to start actuation of machinery to move them apart.

In the present invention the third movement of the operator, that is to say the tripping of the lever to cause the jaws to move apart, is omitted, it being done automatically by mechanism forming part of my improvement.

This feature is supplemented by the provision of means for permitting the parts to be automatically actuated under various pressures.

With these principal objects and advantages in view the invention resides in the novel combination of parts shown in the accompanying drawing, wherein the figure represents a side elevation of a leather stamping machine having my improvement applied thereto.

In the accompanying drawing in order to distinguish that art which is new from the old mechanism, the latter has been shown in light lines only. The machine upon which the invention is mounted consists of a supporting base 1 of suitable size and shape having a hydraulic cylinder 2 at one end and a support 3 extending therefrom to the opposite end. The upper end of this part 3 carries a pivot member 4 to pivotally mount a curved arm 5 thereto. This arm 5 is pivoted intermediate its ends, and one end, namely that disposed over the cylinder 2, is provided with a head 6 which forms one member of the pair of clamping jaws 7 between which the sheets of leather to be embossed are clamped, one or both of said jaws being heated by suitable heating elements disposed therein.

The jaw 7 disposed beneath that formed by the head 6 is mounted on the upper end of a hydraulic piston 8 which is vertically movable within the cylinder 2, said cylinder being supplied with an oil or other fluid undcr pressure through the inlet pipe 9 from any suitable source of supply. From the cylinder 2 this oil flows throughpipes 10 and 11 back to the source of supply, the flow therethrough being continuous when the machine is inoperative.

In the drawing the lower jaw 7 is disposed horizontally, and when operative the upper jaw is also thus disposed and in engagement with the sheet of leather which has been placed on the first jaw. The upper jaw is moved into this horizontal position by rocking the arm 5 around its pivot 4, this being accomplished by raising the end 12 thereof opposite to that upon which the head 6 is formed. This end .12 is connected to the supportin base 1 by means of a pair of links 13 pivoted together as at 14 and having their opposite ends similarly attached to the end 12 and the base 1 respectively.

It is obvious that by moving the links 13 into and out of longitudinal alinement the distance between the end 12 and the base 1 will be varied and the arm 5 thus rocked about its pivot. This movement of the links is readily accomplished by a third link 15 pivoted at one end to the pivot 14 and at its other end to a crank arm 16 carried by a stub shaft 17, the latter being journaled in suitable bearing carried by the portion 3 of the base 1. This shaft 17 also has a gear wheel 18 fixed thereto, the latter being meshed with a pinion 19 on. a shaft 20. A suitable clutch 21 permits'the motion of the continuously rotating shaft 20 to be intermittently transmitted to the pinion 19 and thence to the gear wheel 18. V

The stub shaft17 is thus caused to rotate, in turn rotating the crank arm 16 and moving the links 13 in the manner above mentioned.

In connection with the stub shaft 17 a suitable locking mechanism is provided to retain the upper jaw 7 in either one of two positions, that is to say either in a raised position as shown or in a lowered action.

The locking mechanism consists broadly of a plate 22 having its periphery notched at diametrically opposite points as shown at 23 and 23', and a pivoted lever 24 having a head 25 for engagement with either one of said notches. The plate 22, is fixed to the shaft 17 and rotates therewith, and the lever 24 is pivoted to the portion 3 of the base 1. From this it will be seen that as long as the head 25 remains in either of the notches 23 or 23' it will be impossible to rock the arm 5. One of these notches, namely notch 23, is engaged when the upper jaw 7 is raised, said notch being then disposed above the shaft 17; the other notch 23 is engaged when the two jaws are active, this notch being then dis osed over said shaft 17.

It is desira le that the rotation of the gears 18 and 19 cease immediately upon the engagement of the head 25 in either of the notches, therefore the lever 24 is connected with the clutch 21 by any suitable arrangement of means denoted broadly by the numeral 26. This connection is such that the movement of the lever in one direction will disengage the clutch, while movement in the opposite direction will cause said clutch to become active and permit the rotation of the shaft 21 to be transmitted to the stub shaft 17.

Under ordinary conditions the lever 24 is rocked about its pivot to disengage its head 25 from either of the notches, said head being normally urged into engagement with the periphery of the plate 22 by means of the spring 27, by the movement of a bell crank 28 which has one arm provided with a roller disposed in a slot 29 in the lever 24. The other arm of the bell crank is connected to one end of an intermediately pivoted lever 30 fulcrumed on the base 1, the opposite end of said lever having an actuating member of suitable nature, such as the cable 31, connected therewith. The end of this actuating cable extends from the rear of the machine where it is engaged with the lever 30 to a position adjacent the jaws 7 to readily permit the operator feeding leather to the jaws to actuate the same. It

will be noted that a pull on this cable 31 will cause the lever 30, the bell crank 28, and the lever 24 to rock about their pivots, and simultaneously throw the clutch to an operative position and disengage the head 25 from the notch 23. This movement will start the rotation of the shaft 17, it continuing until the notch 23 is brought into the positionv formerly occupied by notch 23, whereupon the engagement of the head 25 with this notch will stop the operation of the several parts. This half revolution of the shaft 17 is sufficient to move the .upper jaw member downwardly into a horizontal position to be engaged by the upwardly moving lower jaw member, the operation of which will be presently set forth. The upper jaw member will remain in this lowered position until the operator again pulls the cable 31, thereby rocking the several levers and causing the head 25 being disengaged from the notch 23. The shaft 17 will then rotate another half turn before the parts assume the position in the drawing.

lVhile the upper jaw member is in its lowered position the lower jaw member is caused to move toward the same to clamp the sheet of leather therebetween, this upward movement being occasioned by force of the fluid which is caused to flow into the cylinder. When the machine is inoperative this oil flows through the cylinder without collecting therein, since a valve 32 with which the ends of the pipes 10 and 11 are connected is normally open. As soon, however, as this valve 32 is closed the flow of oil through the pipes will be stopped and will thus necessarily collect in the cylinder 2, the increase of.the supply therein raising the piston 8 and its jaw 7. The operation of the valve 32 is preferably automatic, it being simultaneously operated with the rotation of the plate 22, this operation being carried out by the provision of a pin 33 projecting from said plate, and a pivoted arm 34, the latter being adapted to be engaged by said pin. The operating member of the valve 32 is connected to this arm 34, and since the pin is normally engaged therewith, said valve will remain open. As soon, however, as the plate 22 begins to. rotate the pin is moved awa from the arm and the valve is thus permitted to close. The operator of the machine is aided in determining when to separate the jaw members after having pressed a sheet of leathertherebetween, by a pressure gage 35 which is connected through the pipe 36 with the pipe 10 at a point between the valve 32 and a cylinder 2.

The foregoing described machine is provided with means for automatically separating the jaw members 7 when the pressure as indicated by the gage 35 reaches a predetermined point, thus obviating the necessity of relying upon the skill of the operator. 180

With this means the only operations which the mechanic need perform are the placing of the sheets of leather between the jaws 7,

pulling of the cable 31 to move the actuatin mechanism to start rotation of the stub sha t 17 to draw the jaws together, and to remove the stamped sheets of leather after they have been pressed.

The means consists of a fluid operated piston 40 mounted in a cylinder 41 and hav- The lever 43 is pivoted to a link 45 which.

is similarly connected to the base 1, the end of the lever adjacent its connection with the piston stem 42 being dis osed in engagement with one arm of the ell crank 28, preferably that with which the lever 30 is connected. This'end ofthe lever 43 may, if necessary, have an anti-friction roller 46 mounted thereon. The portion of the lever on the other side of its fulcrum has an adjustable weight 47 slidable thereon, this weight being movable toward or away from said fulcrum the amount 0 pressure which must be exerted on the piston 40 before same can be forced downwardly. This end of the lever is adapted to engage a cushioning member 48 provided for an obvious purpose.

It will be seen that when the force of the compressed fluid which is prevented from flowing through the pipe 11 by the closing of the valve 32 has become sufficiently great tomove piston 40 downwardly the lever 43 will trip the bell crank, or rotate it around its fulcrum, the same as if the operator had pulled the cable 31. This movement of the bell crank by the lever 43 will cause the parts to .be actuated in the same manner as set forth when the operator pulled the cable the second time to se arate the jaw members as has been herein efore particularly set forth. The machine is thus not dependent upon the operator for carrying out one of its important functions.

Because of the fact that certain leathers require to be retained between the jaw members 7 a longer time than others, means, in addition to the weight 47, has been provided I for varying the pressures at which the tripping device will become operative. It is obwious that movement of the weight 47 toward or awav from the end of the lever 43 will serve this purpose. Additional regulation is obtained through the provision of a oint to decrease or increasevalve 48' in the pipe 44, the partial opening or closing of which will control the flow of fluid into the cylinder 40.

From the foregoing description taken in connection with the accompanying drawing it will be apparent that a very simply constructed attachment has been provided which will very greatly improve the operation of leather stamping machines, rendering certain of their operations entirely automatic and beyond the control of the operator. Such an arrangement may be obviously employed on other types of machines than that illustrated.

I claim:

1. In a machine of the class described, a supporting base, a pair of pressing members, means for moving one of the said members toward the other, means for retracting said movable member including a bell crank, means for controlling said retractin means comprising a tripping lever engagea le with said bell crank, and means for engagement with said lever to actuate the same. a

2. In a machine of the class described, a pair of pressing members, means for moving one of said members, means for holding the movable member in one position, and means for controlling the last mentioned means including a tripping lever pivoted intermediate its ends, a piston cylinder, a piston movable in said cylinder and connected with said lever to one side of its pivot, and an adjustable weight disposed on the other side of the pivot of said lever.

3. In a machine of the class described, a pair of pressing members, means for moving one of said members toward the other, means for retracting said member including a bell crank, and means for controlling said retracting means comprisinga tripping lever en ageable with the bell crank, a pistoncylin or, and a fluid operated piston therein and connected with the lever.

4. In a machine of the class described, a pair of pressing members, means for moving one of said members toward the other, means for retracting said member including a bell crank, and means for controlling said retracting means comprising an intermediately pivoted tripping lever engageable with said bell crank, a iston cylinder, a piston movable in said cylinder and connected with said tripping lever to one side of its pivot,

and an adjustable weight disposed on the other side of the pivot of said lever.

In testimony that I claim the foregoing I have hereunto set my hand at Milwaukee, in the county of Milwaukee and State of Wisconsin.

BERNARD J. MILLER. 

